In approaching the Clarke, we came to a low basaltic range, which bounded its fine broad openly timbered valley to the northward.

The bed of the river was formed by talc-schiste, in strata, the strike of which was from north by west to south by east, standing almost perpendicular, with a slight dip to the eastward.

The stream was perpendicular on the line of striking.

The pebbles in its bed were mostly basaltic, baked sandstone, conglomerate, quartz, sienite, and porphyry.

I had observed the valley of this river from a high hill near our last camp, and had distinguished many headlands, which I now think were the bluff terminations of lateral basaltic ranges.